Dual wielding pistols would be tight, single pistol seems kind of pointless unless its a high powered caliber such as a revolver or magnum. So to combat use vs other weapon dual wielding pistols could have x2 attacks but still keep their 'weaker than most weapons' title.

Melee weapons could be useful as well, beam swords, regular swords, axes, spears, etc but they would be restricted to ground units only to balance their power / versatility.

Rather than only have bosses unlock certain weapons for players to use, maybe incorporate equipment drops that yield much better gear for players but at a low drop rate so they players can still use weapons they unlock for beating a boss but also beating a boss on a higher difficulty will grant the player access to more powerful stuff as well.

Would be cool if that's what raids unlocked, equipment. I don't think an sc2 arcade game should use too much rng, not many groups would stick around the grind the same boss many times for a chance at some boots imo.

Melee weapons are mainly used in certain abilities. Some of these are commonly found in the ghosts abilities. The reason other classes dont have melee attacks is that the unit does not have an animation for it. Il search the heroes animations again and see if I can find any other units that may have it aswell.

Gear does randomly drop for killing bosses. This was added recently. Although this does not drop weapons.

And for the pistols, I do hope on adding such weapons. I would personally like to add more types of weapons.